In the operation of apparatus for the inspection of glass containers, it is assumed that automatic inspection may be made better than manual or visual inspection by operators. This invention relates to an apparatus for inspecting glassware and in particular to apparatus for inspecting the sidewall of hollow glass containers for defects which are of an optically distinguishable character. As might be expected, in the manufacture of blown hollow glass containers it sometimes happens that the sidewall of the container, that is that portion of the container below the finish or neck of the bottle and above the curved heel and bottom of the bottle, has defects which would affect the performance of the container in service. It is important that every blown glass container have its sidewall, among other portions of the container, inspected for defects and it would be a great advantage if these containers could be inspected at high speeds with a high degree of reliability so that when a container passes the inspection, it would be positively free of defects in the sidewall thereof.
In the past, there have been inspection devices which would inspect containers for defects in the finish portion such as "line-over-finishes," "checks" (both vertical and horizontal), "seeds" and "blisters." Further, there have been bottom and heel check detectors which operate on the principle of optical reflectance or refraction. Furthermore, there have been inspection devices which inspected the containers to ensure that their height is correct, that the finish of the bottle is free of "dips and warps" and that the finish of the container not be cocked or out of alignment with the general central vertical axis of the container. Such an inspection apparatus may be found by reference to U.S. Pat. No. 3,313,409 issued to J. R. Johnson and assigned to the Assignee of the present application.
The disclosure of this U.S. Pat. No. 3,313,409 is incorporated herein by reference thereto. A reading of this patent will indicate that there are four inspection stations in the inspection device which are labeled II, III, IV and V. While the present disclosure is directed specifically to the inspection of the sidewall area of a glass container, the invention should be considered in its broader sense as a system for inspecting at any one of the stations as depicted in the above-referred-to Johnson patent.
In the present disclosure, only one station of the inspection machine is disclosed in detail, inasmuch as this is the station in which the containers are to be inspected for sidewall defects by the system of the invention. While the Johnson patent is dealing with what would appear to be fairly small size containers, the general principle of operation of the device is one which would readily lend itself to the handling of a plurality of larger size containers through a series of inspection stations by having the ware brought to the machine with the turret or head then being indexed through approximately a 45.degree. angle of rotation. This indexing motion carries the containers in the present invention through five inspection positions with a first position in advance of the first inspection station being in alignment with a conveyor that bring the bottles into the machine followed by five inspection positions and then followed by an exit position. Intermediate the exit position and the entrance position is what is termed a "reject position" or zone where bottles which have been sensed as defective by the apparatus, are retained in the apparatus so as to be cleared from the apparatus turret at this intermediate position. At this position, a cullet bin or other defective container disposal chute may be positioned. Frequently, these bottles which are rejected are returned, by a suitable coveying system, to the forming area where the forming operator may examine the container and in this way determine what might be an appropriate change to the process or to the machinery being used to correct any ongoing or long-term defect which is being produced. As in many manufacturing processes, defects sometimes crop up without any apparent reason, while in other instances a defect may appear and continue to appear through a period of production. These types of recurring defects are those which the present invention is most capable of determining and alerting the operators to the situation. Furthermore, any glass container which is made with any kind of a structural defect which might affect its performance in the market place is gauged, inspected and discarded when such a defect is detected, no matter for what reason the defect may have been produced.
It will be noted that the starwheel or indexing mechanism head of the prior art shown in the above-mentioned U.S. Pat. No. 3,313,409 consists generally of a pair of flat plates having notches formed in the periphery thereof within which containers to be inspected are serially placed. The starwheel of the present invention is considerably modified and improved for the purpose of handling containers in such a manner that they may be successfully inspected by illumination of the sidewall of the container to its full height. This is something which has not been easily achievable in prior devices where multiple inspections are being made. It has also been the practice in the past to move containers down a conveyor and, in effect, use a pair of TV cameras looking at the bottle at two angles in an effort to determine whether or not a container is of an acceptable appearance or shape. One serious drawback with such a device has been the inability to completely examine 360.degree. of the container sidewall without distortion being injected into the system due to the fact that the edges of the container produce optical refractance and reflectance aberrations in the images viewed by the cameras.
With the foregoing in view, it is an object of the present invention to provide apparatus which is capable of moving glass containers through a series of inspection positions where various types of inspection may be carried out, with one of the positions being the location of a novel optical sidewall inspection device. Such sidewall inspection device comprises a source of illumination which will cover substantially the full height of the container and illuminate a vertical section of the sidewall from behind. Further, the source of illumination is variable in its intensity to provide greater illumination for containers that are formed of colored glass such as "amber," and to vary the intensity of the light at selected areas of the bottle depending on the shapes thereof.
The illuminated sidewall is viewed by a camera that is mounted outboard of the handling system. The camera is composed of a linear array of photosensitive devices onto which the illuminated image of the sidewall section is focused, with the array being scanned electronically and with the outputs being processed by microprocessor.
It is a further object of the invention to provide a container handling system capable of high speed operation and smooth handling of containers into and out of the indexing head or starwheel. The invention further consists of an improved starwheel construction which will permit rotation of a container at the sidewall inspection station without blocking the view of the camera and a novel mechanism to assist the movement of the containers out of the starwheel at the exit position.
Other and further objects will be apparent from the following detailed description taken in conjunction with the accompanying drawings.